Archive for the Kids Category
one positive news item from the Middle East
Posted in Kids, Travel, University life with tags death penalty, Law Faculty, Lebanon, Middle East, Together against the death penalty, University of Oxford on August 22, 2026 by xi'an
watching the eclipse
Posted in Kids, pictures, Running, Travel with tags 20h17, eclipse, ghost image, jatp, Parc de Sceaux, Sceaux, solar eclipse, sunset on August 21, 2026 by xi'an
and it is getting worse… [verbatim]
Posted in Books, Kids, pictures with tags Agent Orange, Amish communities, antivaxers, autism, baby Trump, BBC, cliffs, Derailed Trump, Donald Trump, measles, populism, quotes, religious communities, US politics, vaccines, WHO on August 19, 2026 by xi'an
“In many cases we were requiring 72 jabs for our beautiful, healthy, lovely, delicate little children“ — DT, 10 Aug. 2026
“[Autism] is many, many times what it used to be years ago, and it gets progressively worse. And we had progressively more and more vaccines” — DT, 10 Aug. 2026
“A vaccination looks like the size of the bottle of soda poured into a little child’s body“ — DT, 10 Aug. 2026
“Decades ago, children received only a small fraction of the vaccines required today. In those times, people were much [healthier], and of course, the high rates of autism now observed did not exist” — DT, 10 Aug. 2026
“When you and I were kids, everybody got measles, and measles gave you … lifetime protection against measles infection. The vaccine doesn’t do that. The vaccine is effective for some people for life, but for many people, it wanes” — Robert F Kennedy, March 2026
“Those agencies are going to do everything in their power to make the Amish vaccinate. Because they cannot stand the fact that you are healthy.” — Robert F Kennedy, 10 Aug. 2021
“The communities that are suffering from measles are almost all religious communities that just don’t vaccinate” — Robert F Kennedy, 2 Aug. 2026
post-vacation tee-shirt design
Posted in Kids, Mountains, pictures, Travel with tags Ainu, animism, Þe Norse face, brown bear, copycat, grizzly bear, higuma, Hokkaido, Japan, katakana, tee-shirt, TNF on August 16, 2026 by xi'an
Round-robin (with Claude)
Posted in Books, Kids, R, Statistics, Wines with tags AI, Auvergne, écir, bougnat, café, Claude, LLMs, mathematical puzzle, Paris, simulation, Springer Nature, Statistics and Computing, The Fiddler on August 15, 2026 by xi'an
A few days ago I had a coffee in Paris with my long-time friend (and former Statistics & Computing editor) Gilles Celeux, and he mentioned me stopping solving and posting maths puzzles like those weekly published by Le Monde. They have indeed vanished with the retirement of the authors, but Gilles added that the arrival of LLMs would have made the exercise moot. I disagreed as (i) the fun of solving the puzzle on my own has not gone away and (ii) the pedagogical appeal of the puzzle and its resolution remains. As the next Fiddler puzzle arrived in my mailbox, my resolution was put to the test (contrariwise to the previous entry, which did not require massive computations):
The Fiddler League consists of two teams. Over a season, they play each other 162 times. Each team has an equal chance of winning each game, and the results of games are independent. Over the season, on average, how many games would you expect the team with the better record to have won?
I started on the wrong foot with E[X|X≥81] when X is Bin(162,½), equal to 85.77 (either directly or with a Normal approximation), which differs from my second thought, E[max(X,162-X)]=86.07 (either directly or with a Normal approximation), which is larger because of the reflection produced by max. While the first computation was manageable, the second one seemed to involve simulation and I caved in prompting Claude, which provided the answer along with the connection
E[max(X,162−X)]=E[X∣X≥81](1+p81)−81p81
After some expansion, the League boasts 30 teams. Over a season, each team plays each other team five times. (Each team plays a total of 145 games.) Again, each team has an equal chance of winning each game, and the results of games are independent. Over the season, on average, how many games would you expect the team with the best record to have won?
The best record is max(Xi) with each of the 30 Xi‘s a sum of 29 Yij and the Yij=5-Yji distributed as Bin(5,½). The Xi‘s are thus Bin (145,½) but dependent. While I could not figure out a closed form answer for the expectation, a direct Monte Carlo resolution is obviously feasible, with Claude (rather than me) running it over 400 million repetitions, but a 30 dimensional Normal approximation exploiting the correlation of 1/29 between the components leads to roughly 85 as the expected value. (Again computed by a Claudicant simulation.)
While the conclusion that the Normal approximation is pretty accurate with so many terms in the Binomial variates is quite unsurprising, Claude saves me coding time without ruining the puzzle altogether. (And Gemini made me aware that the name of the café where Gilles and I regularly meet, L’Écir, is an Auvergne noun for a local, dangerous, mountain blizzard! Thus linking the place to the foundation of the café by Auvergne expatriates…)
